The Arsenal forward was substituted six minutes from time during the 3-3 draw with Fulham on Saturday and Gunners boss Arsene Wenger confirmed he had picked up a knock.
The Frenchman said Walcott would need to be assessed ahead of next Wednesday's friendly match in Stockholm.
"Walcott has a glute muscle problem," said Wenger. "We nearly took him off at half-time, he nearly went down, but we left him on and on.
"In the end, it got worse and worse. At the moment, he is limping so I do not know whether he will be able to join the national team or not."